1. Technical Field
The present invention relates to a suction device that sucks out a liquid, with which an ejection head provided with a nozzle has been filled, from the nozzle, a suction method that eliminates clogging of the nozzle, and an ejection device provided with the suction device.
2. Related Art
As an example of the ejection head described above, there is known an ink jet head that includes a plurality of nozzles, a compression chamber that is provided in each of the plurality of nozzles and that is in communication with the corresponding nozzle, an actuator provided in each compression chamber, and a cavity that is commonly in communication with the compression chambers provided in the nozzles. A printing apparatus (printer), for example, provided with such an ink jet head is capable of drawing characters and graphics onto an object to be ejected, such as a sheet of recording paper, by ejecting ink, which is a liquid, from the nozzles in the form of droplets onto the object to be ejected.
In the printing apparatus (printer) described above, if a nozzle of the ink jet head is clogged by solidified ink, foreign matter, or bubbles, ink will not be ejected from the nozzle or a failure such as flight deflection, a failure in which the ink fails to land at the desired position on the object to be ejected, will occur. Accordingly, there are cases in which the desired printing results cannot be obtained. Therefore, the printing apparatus described above is provided with a maintenance mechanism that eliminates clogging of the plurality of nozzles of the ink jet head.
For example, Japanese Patent No. 4010854 discloses an apparatus for manufacturing a functional element substrate in which the apparatus includes a reliability maintaining device having an elastic cap that is pressed onto an ejection head (ink jet head) to seal nozzles and a suction pump that performs sucking from a hole that is in communication with the elastic cap.
A solution that is fed to the ejection head is retained in a separate container and the container and the ejection head are connected through a flexible supply line. At least two types of filters are provided downstream of the container. The filter provided most downstream is incorporated into the ejection head in a non-detachable manner, and the filter upstream of the most downstream filter is provided in a detachable manner. The filter provided most downstream has a smaller filter capacity and a larger filter mesh size than the filter provided upstream. Furthermore, the above-mentioned Japanese Patent No. 4010854 states that the amount of solution sucked by the reliability maintaining device is equivalent to or larger than the internal volume of the area downstream of the filter provided most downstream. Accordingly, the above-mentioned Japanese Patent No. 4010854 states that clogging of the ejection head can be eliminated and the apparatus for manufacturing a functional element substrate can be operated in a stable manner.
The above-mentioned Japanese Patent No. 4010854 states that the required minimum quantity of the suction volume of the solution of the reliability maintaining device has been made clear. However, setting the suction volume of the suction pump does not necessarily achieve reliable suction of the required minimum quantity of solution. For example, depending on the decompressed state of the flexible supply line between the elastic cap and the suction pump, the suction volume may disadvantageously change. In other words, more than the amount of solution required to eliminate the clogging of the nozzle may be excessively sucked. Furthermore, since foreign matter may be disadvantageously included in the sucked solution, it is difficult to reuse the sucked solution after the sucked solution is discharged. Accordingly, when the solution is very expensive, a demand for reducing the amount of solution that is sucked and disposed arises. In other words, there is a need to reduce the amount of solution that is sucked for eliminating clogging of the nozzles as much as possible.